This application relates to and claims priority to corresponding Japanese Patent Application No. 182203/2000 filed on Jun. 16, 2000.
1. Field of the Invention
The present invention relates to a granular object sorting apparatus for sorting out a particular granular object wherein diffusion light from granular objects of raw materials to be sorted is received and each object is subjected to the determination as to whether it is acceptable or unacceptable based on the received diffusion light. More specifically, the present invention relates to an ejection means used in such sorting apparatus.
2. Description of the Related Art
Japanese Patent Application Kokai-Publication No. Hei 9-113454 discloses an ejection means for a grain sorting apparatus, which is constructed by a plate spring means arranged at a point downstream of a point where the grains are image-taken by a CCD camera and divided into a plurality of plate sections along a transverse direction with respect to the falling locus of the grains; a plurality of solenoid means for deforming corresponding plate sections of the plate spring means; and a solenoid control means for selectively supplying driving power to the solenoid means. The falling locus of the grain is changed by the deviation of the corresponding plate section of the plate spring means and by the direct hitting thereof against the grains in such divided plate sections whereby sorting out of the unacceptable ones from the acceptable ones is performed.
As compared to the conventional ejecting means in which an ejector nozzle for outputting jet air is provided, the above explained ejecting means is very advantageous in term of cost because it does not need the air source. Further, because it does not need the air conduits which have conventionally crossed with the electric wirings, its inner construction structured mainly by the electric wirings is very simple. In addition, as the maintenance is necessary only for the electric wirings, it can be said that the total maintenance required is reduced to half.
However, since the solenoid has such a construction that either one of the retracting or projecting-out operation of the reciprocating rod thereof is dependent on such a resilient member as a coil spring, there is a limit in response performance of the retracting and projecting-out operation of the reciprocating rod. For this reason, in the case where such solenoid is used as an ejecting means, there is an inevitable limit in the sorting performance.
In this connection, the applicant of the present application filed a patent application (Patent Application No. Hei 11-365740) for a granular object sorting apparatus in which the solenoid having the improved response performance of the retracting or projecting-out operation over the conventional solenoids is used as a sorting means. Such solenoid is configured such that the reciprocating rod is provided with permanent magnets and with a further permanent magnets which surround the reciprocating rod so as to bear the reciprocating rod in a non-sliding state or a floating state and, by the ON/OFF action of the reciprocating means configured by the permanent magnets on the reciprocating rod and the electromagnetic coils surrounding the reciprocating rod, the retracting or the projecting-out operation of the reciprocating rod is caused. Since, in this way, the reciprocating rod is borne in the non-sliding state, the response performance of the retracting and projecting-out operation of the reciprocating rod has been improved over that of the conventionally available solenoid. Unacceptable granular objects are ejected or sorted out at the tip portion of the reciprocating rod of the solenoid.
However, in the case where the granular objects to be ejected by a given solenoid (ejection means) flow continuously, there was a concern that such granular objects may not be ejected merely by improving the response performance of the retracting and projecting-out operation of the reciprocating rod. The problem resides in the space in which the granular objects continuously flow. Between the contiguous granular objects, there can be a space which allows the ejection of both the granular objects by the response of the reciprocating rod of the solenoid and there can also be a space which does not allow the ejection by such response of the reciprocating rod. In the latter case, even though the first granular object could have been ejected, the second granular object could not be ejected because the projecting-out operation of the reciprocating rod is not made in time so that such unacceptable granular object of the second one flows through together with the acceptable granular objects.
Therefore, an object of the present invention is to provide a granular object sorting apparatus in which, even when the granular objects to be ejected by a given ejection means flow-in continuously, these granular objects are appropriately ejected thereby improving and enhancing a sorting precision over that in the conventional apparatuses.
In order to solve the above problems, the present invention provides a granular object sorting apparatus in which, at a point along a falling locus of the granular object released from a transfer means which transfers granular objects to be sorted, there are provided an illuminating means for irradiating light to the granular object; a light receiving means for receiving light from the granular object having received irradiating light of the illuminating means; and an ejection means for ejecting the granular object to be ejected; and in which there are provided a determination means for determining the granular objects to be ejected based on a received light signal from the light receiving means; and a driver circuit for outputting a driving signal to the ejection means based on an ejection signal from the determination means,
said ejection means being provided with a reciprocating rod which is borne in a non-sliding state and which linearly projects out or retracts in an axial direction; and a reciprocating means for causing the reciprocating rod to retract or project out by the driving signal from the driver circuit and, at the tip portion of the reciprocating rod, there is provided a slanted surface inclining towards the projecting-out direction of the reciprocating rod from the upstream side of the falling locus, with the slanted surface hitting the granular object in the falling locus during the projecting-out operation of the reciprocating rod; and it is arranged that the driver circuit outputs a driving signal to the reciprocating means so that, when the granular objects to be ejected by a given ejection means are determined as contiguous, the retracting or projecting-out operation of the reciprocating rod is caused correspondingly in such a manner that the reciprocating rod is projected out according to the first (leading) granular object to be ejected and, after the ejection of all the second or succeeding granular object(s) to be ejected, the retracting operation takes place.
The ejection means which effects the ejection of the falling granular objects by the reciprocating rod is configured such that the reciprocating rod is in a non-sliding state so that there is no possibility for the reciprocating rod to be subjected to any load caused by sliding friction in the reciprocating rod during the retracting or projecting-out operation thereof. Further, since the granular objects to be ejected are directly removed by the reciprocating rod, it is sufficient that the ejection means has only a pressing power to eject the granular object. Therefore, as compared to the conventional ejection means, it is possible to make the ejection means of the invention compact, which requires a small driving power. Still further, since the reciprocating rod is projected out or retracted by the reciprocating means, without depending on such as a coil spring for either one of the projecting-out and retracting operations and also the reciprocating rod is borne in a non-sliding or floating manner, the arrangement can achieve the response performance as good as the conventional air type ejector, thus enabling the maintenance of the same productivity as before and also enabling, with the dispensing of any air source, the provision of an energy-saving granular object sorting apparatus. Further, at the foremost end portion of the reciprocating rod, there is provided a slanted surface inclining towards the projecting-out direction of the reciprocating rod from the upstream side of the falling locus, with the slanted surface hitting the granular object in the falling locus during the projecting-out operation of the reciprocating rod, and it is arranged that the driver circuit outputs a driving signal to the reciprocating means so that, when the granular objects to be ejected by a given ejection means are determined as contiguous, the projecting-out operation of the reciprocating rod is caused correspondingly to the leading granular object to be ejected and, after the ejection of the succeeding granular object or objects to be ejected, the retracting operation takes place. Thus, the leading defective granular object is ejected by the slanted surface of the reciprocating rod which projects out correspondingly to the leading granular object, and the second defective granular object succeeding to the leading granular object is ejected by being hit by the slanted surface of the reciprocating rod held in the projected-out state. The reciprocating rod performs the retracting operation after the ejection of the second granular object. Thus, even when the defective granular objects to be ejected by a given ejection means flow-in continuously, these granular objects are ejected so that the grain sorting precision is improved and enhanced. In addition, since the frequency or number of the projecting-out and retracting operation required to the reciprocating rod decreases as compared to the conventional ones, wear of the ejection means can be made small.
Further, the ejection means is configured such that, by permanent magnets provided on the reciprocating rod and permanent magnets provided to surround the reciprocating rod, the reciprocating rod is borne in a non-sliding state and, by the ON/OFF action of the reciprocating means configured by the permanent magnets on the reciprocating rod and the electromagnetic coils surrounding the reciprocating rod, it is made possible to effect the retracting or projecting-out operation of the reciprocating rod. In this way, by utilizing the repelling action between the permanent magnets on the reciprocating rod and the electromagnetic coils surrounding the reciprocating rod, it is made possible for the bearing of the reciprocating rod to be in a non-sliding state and, by utilizing the repelling action/attracting action of the permanent magnet of the reciprocating rod and the electromagnetic coils surrounding the same, it is made possible for the reciprocating rod to assume the retracting and projecting-out operations. In this way, the retracting and projecting-out operations can be controlled independently by the ejection means itself. Also, since the retracting and projecting-out operations are in a non-sliding state, it is possible for the reciprocating rod to be driven in the extent of 2 ms, which amounts to the same response speed as in a conventional ejector type means in which air is jetted.
Usually, the ejection means is used by placing it in a transverse direction of the flow of the granular objects, with a plurality of the ejection means being positioned in the transverse direction. The plurality of ejection means are preferred to be arranged in a zigzag manner. That is, where the reciprocating rods are arranged in a zigzag manner, even when the area occupied by one reciprocating means is larger than one granular object, the reciprocating rods may be arranged without gaps in the transverse direction. This is because the ejection means of the present invention provides ejecting function independently and does not require a separate member such as a plate spring so that the plurality of ejection means may be arranged in any desired manner.